The invention concerns a device for unwinding a web of material from a reel, with two supporting arms that are positioned separated and extending across the web, that can be pivoted up, and that have means of accommodating and holding the reel in such a way that it can be rotated.
Devices of this type are intended especially for unwinding webs of paper in the paper-processing industry.
The reels of paper that are to be unwound are suspended between the supporting arms and lifted for unwinding a web of paper that is wound on a core tube is to be unwound without a shaft, two expanding chucks that rotate on the arms are introduced into the openings on each side of the tube. Unwinding devices of this type are described in German No. GM 8 511 986 and OS 2 951 336 for example.
When the reels are changed, fresh reels are usually supplied by means of under-the-floor conveyors that advance them into the pick-up range of the chucks, which can be separated and lowered in order to accept the reel. When several reels distributed along the direction that the web is traveling in are to be unwound, it is practical, in order to accelerate changing the reels, to introduce the new reels from the side, across the direction of travel. When the arms of the devices are secured in lateral uprights, enough space must be left between the unwinding stations because the uprights get in the way of lateral loading and the reels must also be advanced along the direction of travel to position them within the range of the chucks.
In order to eliminate the need for this additional motion and to attain a space-saving design, the supporting beams in the generic device described in German No. GM 8 511 986, which are suspended in a stand, are pivoted up on the loading side to allow a fresh reel to be introduced. The beams pivot up into a vertical position to accommodate the fresh reel, and the arms are subsequently shortened in order to lift the reel. There is a drawback to this device in that all the forces must be transmitted by horizontal supporting components of the stand, which must accordingly be very heavy to attain the requisite stability.
Also known are devices in which the supporting arms move up and down vertically on uprights and can also be pivoted up to introduce a fresh reel. The arms, which are separated more or less horizontally, travel vertically in the uprights for lifting into the unwinding position. This demands expensive perpendicular channeling of the arms in the lateral uprights.